Cardiovascular system
April 2019
C-N02 (NP)

Signalment (JPC #2630322):  Old military working dog

HISTORY:  This dog had a mass on the right atrium of the heart.

HISTOPATHOLOGIC DESCRIPTION:  Heart, right atrium:  Expanding the myocardium and replacing 95% of cardiac myocytes, is an unencapsulated, poorly circumscribed, poorly demarcated, moderately cellular, infiltrative neoplasm composed of spindle cells forming irregularly sized blood-filled vascular channels, often wrapping collagen or rarely forming streams, bundles or more solidly cellular areas.  Neoplastic cells have variably distinct cell borders,  moderate amount of eosinophilic fibrillar cytoplasm, irregularly oval to elongate nuclei that occasionally bulge into vascular channels, coarsely clumped chromatin and up to 2 distinct nucleoli.  Mitosis averages 3-5 per 40 x high power field.  Anisokaryosis and anisocytosis are marked. Subjacent cardiac myocytes are swollen and pale (degenerate) or shrunken and hypereosinophilic with pyknotic nuclei (necrotic).There are and few fibrin thrombi, scattered single cell necrosis, scattered aggregates of lymphocytes, plasma cells, hemosiderin-laden macrophages, and viable and degenerate neutrophils.  Surrounding the neoplastic cells is abundant hemorrhage, large coalescing areas of bright eosinophilic polymerized fibrin admixed with small amounts of necrotic debris, hematoiden and low numbers of hemosiderin laden macrophages.

MORPHOLOGIC DIAGNOSIS:  Heart, right atrium:  Hemangiosarcoma, breed not specified, canine.









Gross masses in or near the heart:

Histologic differential diagnosis for vascular proliferations: 


Hemangiosarcoma in other species:


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